Feeder for punch

ABSTRACT

A feeder is provided for a punch. The feeder includes a feeding unit, a bending unit and a transferring unit. The feeding unit feeds a roll of a metal strip that includes a leading edge. The bending unit includes a plate for bending the metal strip, a sensor for generating at least one signal on detecting the arrival of the leading edge of the metal strip at the plate and a controller for actuating the plate on receiving the signal. The transferring unit transfers the metal strip to another unit of the punch.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a punch and, more particularly, to a feeder for a punch.

2. Related Prior Art

Referring to FIGS. 5 through 7, there is shown a conventional feeder for a punch. The feeder includes a feeding unit 1, a guiding unit 4, a bending unit 3 and a transferring unit 2. A metal strip or plate 5 is rolled. The roll is installed on the feeding unit 1. The feeding unit 1 rotates the roll so as to feed the metal strip 5. The guiding unit 4 guides the metal strip 5 to the bending unit 3. When reaching the bending unit 3, a leading edge of the metal strip 5 travels counterclockwise at a large curvature. The bending unit 3 pivots so as to bend the metal strip 5. When leaving the bending unit 3, the leading edge of the metal strip 5 travels clockwise at a small curvature. The bending unit 3 guides the metal strip 5 to the transferring unit 2. The transferring unit 2 transfers the metal strip 5 to another unit of the punch. The rotation of the feeding unit 1 and the pivoting of the bending unit 3 must be coordinated. The coordination is conducted manually. To this end, there are buttons 6 and 7 for controlling the rotation of the feeding unit 1 and the pivoting of the bending unit 3, respectively. It however requires an experienced and concentrated operator to precisely operate the buttons 6 and 7. Otherwise, undesired situations would occur. Referring to FIG. 6, the rotation of the feeding unit 1 is too fast while the pivoting of the bending unit 3 is too slow so that the leading edge of the metal strip 5 is too high for the transferring unit 2 to receive. Referring to FIG. 7, the rotation of the feeding unit 1 is too slow while the pivoting of the bending unit 3 is too fast so that the bending unit 3 hinders the advancing of the leading edge of the metal strip 5.

The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.

SUMMARY OF INVENTION

According to the present invention, a feeder is provided for a punch. The feeder includes a feeding unit, a bending unit and a transferring unit. The feeding unit feeds a roll of a metal strip that includes a leading edge. The bending unit includes a plate for bending the metal strip, a sensor for generating at least one signal on detecting the arrival of the leading edge of the metal strip at the plate and a controller for actuating the plate on receiving the signal. The transferring unit transfers the metal strip to another unit of the punch.

An advantage of the feeder of the present invention is improved safety for an operator since the operator can stay away from the bending unit because of the automatic operation of the bending unit.

Another advantage of the feeder of the present invention is improved throughput due to the automatic operation of the bending unit.

Other advantages and features of the present invention will become apparent from the following description referring to the drawings.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be described through detailed illustration of the preferred embodiment referring to the drawings.

FIG. 1 is a side view of a feeder for a punch according to the preferred embodiment of the present invention.

FIG. 2 is a side view of the feeder in another position than shown in FIG. 1.

FIG. 3 is a side view of the feeder in another position than shown in FIG. 2.

FIG. 4 is a side view of the feeder in another position than shown in FIG. 3.

FIG. 5 is a side view of a conventional feeder for a punch.

FIG. 6 is a side view of the feeder in another position than shown in FIG. 5.

FIG. 7 is a side view of the feeder in another position than shown in FIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIGS. 1 through 4, there is shown a feeder for a punch according to the preferred embodiment of the present invention. The feeder includes a feeding unit 10, a bending unit 30 and a transferring unit 20. A metal strip 40 is rolled. The roll of the metal strip 40 is installed on the feeding unit 10. The feeding unit 10 rotates the roll so as to feed the metal strip 40. On reaching the bending unit 30, a leading edge 41 of the metal strip 40 travels at a large curvature. The bending unit 30 pivots so as to bend the metal strip 40. When leaving the bending unit 30, the leading edge 41 of the metal strip 40 travels at a small opposite curvature. The bending unit 30 guides the metal strip 40 to the transferring unit 20. The transferring unit 20 transfers the metal strip 40 to another unit of the punch.

The feeding unit 10 includes a shaft 11 for rotation and a plurality of spoke-liked extenders 111 extensible from the shaft 11 to the roll of the metal strip 40. The shaft 11 rotates the roll of the metal strip 40 through the extenders 111. The feeding unit 10 includes a restraint 12, an abutting element 13 and a guiding element 14. The restraint 12, abutting element 13 and the guiding element 14 are conventional and will not be described in detail. The guiding element 14 guides the metal strip 40 to the bending unit 30.

The bending unit 30 includes a plate 33 for contact with the metal strip 40, an arm 32 for pivoting the plate 33 and a cylinder 321 for driving the arm 32. The plate 33 includes a first edge 331 and a second edge 332. The cylinder 321 may be hydraulic or pneumatic. The cylinder 321 may be replaced with an electrical mechanism.

The transferring unit 20 includes first pair of driving rollers 21, a second pair of driving rollers 22 and a group of flattening rollers 23.

The rotation of the feeding unit 10 and the pivoting of the bending unit 30 must be coordinated. The rotation of the feeding unit 10 is controlled manually. The pivoting of the bending unit 30 is controlled automatically. To this end, a sensor 34 and a controller 31 are used. The sensor 34 is attached to the plate 33 near the second edge 332. The sensor 34 is preferably embedded in the plate 33 for protection from the leading edge 41 of the metal strip 40. The controller 31 is electrically connected to the sensor 34 on one hand and operatively connected to the cylinder 321 on the other hand. The controller 31 receives signals from the sensor 34 and accordingly actuates the cylinder 321. The pivoting of the bending unit 30 is conducted at two steps.

Referring to FIG. 1, the leading edge 41 of the metal strip 40 reaches the sensor 34. On detecting the arrival of the metal strip 40, the sensor 34 sends a signal to the controller 31 that in turn actuates the cylinder 321. The arm 32 pivots the plate 33, and this is the first step.

Referring to FIG. 2, the sensor 34 departs from the metal strip 40 since the plate 33 moves faster than the metal strip 40. The pivoting of the plate 33 is stopped.

Referring to FIG. 3, the advancing of the metal strip 40 continues so that the leading edge 41 of the metal strip 40 reaches the sensor 34 again. On detecting the arrival of the metal strip 40 again, the sensor 34 sends a signal to the controller 31 that in turn actuates the cylinder 321 again. The arm 32 pivots the plate 33 again, and this is the second step.

Referring to FIG. 4, the pivoting of the plate 33 is stopped so that the position of the plate 33 is retained. The metal strip 40 continues to advance and enter the transferring unit 20. The transferring unit 20 flattens and transfers the metal strip 40 to another unit of the punch.

When a tail edge of the metal strip 40 moves beyond the sensor 34, the sensor 34 detects the departure and sends a signal to the controller 31 that in turn actuates the cylinder 321 in an opposite direction. The arm 32 returns the plate 33 to its original position.

The feeder of the present invention exhibits at least two advantages. Firstly, for the automatic operation of the bending unit 30, an operator can stay away from the bending unit 30 so that the operator operates the feeder of the present invention safer than he or she does a conventional feeder. Secondly, for the automatic operation of the bending unit 30, the throughput of the feeder of the present invention is faster than that of a conventional feeder.

The present invention has been described through the illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims. 

1. A feeder for a punch, the feeder comprising: a feeding unit for feeding a roll of a metal strip that includes a leading edge; a bending unit comprising a plate for bending the metal strip, a sensor for generating at least one signal on detecting the arrival of the leading edge of the metal strip at the plate and a controller for actuating the plate on receiving the signal; and a transferring unit for transferring the metal strip from the bending unit to another unit of the punch.
 2. The feeder according to claim 1 wherein the operation of the plate comprises a first step and a second step.
 3. The feeder according to claim 2 wherein on detecting the arrival of the leading edge of the metal strip, the sensor sends a first signal to the controller that in turn causes the plate to pivot faster than the metal strip advances so that the plate departs from the leading edge in the first step, wherein on detecting the arrival of the leading edge of the metal strip again, the sensor sends a second signal to the controller that in turn causes the plate to pivot further in the second step.
 4. The feeder according to claim 1 wherein the sensor is embedded in the plate.
 5. The feeder according to claim 1 wherein the plate comprises a first edge and a second edge closer to the feeding unit than the first edge is, wherein the sensor is located near the second edge.
 6. The feeder according to claim 1 wherein the bending unit comprises an arm for pivoting the plate.
 7. The feeder according to claim 6 wherein the bending unit comprises a mechanism for rocking the arm.
 8. The feeder according to claim 7 wherein the mechanism is a cylinder.
 9. The feeder according to claim 8 wherein the cylinder is hydraulic.
 10. The feeder according to claim 8 wherein the cylinder is pneumatic.
 11. The feeder according to claim 1 wherein the feeding unit comprises a restraint for restraining the metal strip.
 12. The feeder according to claim 11 wherein the feeding unit comprises an abutting element for abutting the metal strip after the restraint.
 13. The feeder according to claim 12 wherein the feeding unit comprises a guiding element for guiding the metal strip to the bending unit after the abutting element.
 14. The feeder according to claim 1 wherein the transferring unit comprises at least one pair of driving rollers for rolling and driving the metal strip.
 15. The feeder according to claim 14 wherein the transferring unit comprises, near the driving rollers, a group of flattening rollers for rolling and flattening the metal strip. 